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Long-term planning versus short-term planning in the asymptotical location problem

Alessio Brancolini, Giuseppe Buttazzo, Filippo Santambrogio, Eugene Stepanov (2009)

ESAIM: Control, Optimisation and Calculus of Variations

Given the probability measure ν over the given region Ω n , we consider the optimal location of a set Σ composed by n points in Ω in order to minimize the average distance Σ Ω dist ( x , Σ ) d ν (the classical optimal facility location problem). The paper compares two strategies to find optimal configurations: the long-term one which consists in placing all n points at once in an optimal position, and the short-term one which consists in placing the points one by one adding at each step at most one point and preserving...

Long-term planning versus short-term planning in the asymptotical location problem

Alessio Brancolini, Giuseppe Buttazzo, Filippo Santambrogio, Eugene Stepanov (2008)

ESAIM: Control, Optimisation and Calculus of Variations

Given the probability measure ν over the given region Ω n , we consider the optimal location of a set Σ composed by n points in Ω in order to minimize the average distance Σ Ω dist ( x , Σ ) d ν (the classical optimal facility location problem). The paper compares two strategies to find optimal configurations: the long-term one which consists in placing all n points at once in an optimal position, and the short-term one which consists in placing the points one by one adding at each step at most one point and preserving...

Lower large deviations and laws of large numbers for maximal flows through a box in first passage percolation

Raphaël Rossignol, Marie Théret (2010)

Annales de l'I.H.P. Probabilités et statistiques

We consider the standard first passage percolation model in ℤd for d≥2. We are interested in two quantities, the maximal flow τ between the lower half and the upper half of the box, and the maximal flow ϕ between the top and the bottom of the box. A standard subadditive argument yields the law of large numbers for τ in rational directions. Kesten and Zhang have proved the law of large numbers for τ and ϕ when the sides of the box are parallel to the coordinate hyperplanes: the two variables grow...

Lower large deviations for the maximal flow through tilted cylinders in two-dimensional first passage percolation

Raphaël Rossignol, Marie Théret (2013)

ESAIM: Probability and Statistics

Equip the edges of the lattice ℤ2 with i.i.d. random capacities. A law of large numbers is known for the maximal flow crossing a rectangle in ℝ2 when the side lengths of the rectangle go to infinity. We prove that the lower large deviations are of surface order, and we prove the corresponding large deviation principle from below. This extends and improves previous large deviations results of Grimmett and Kesten [9] obtained for boxes of particular orientation.

Machine Repair Problem in Production Systems with Spares and Server Vacations

Jau-Chuan Ke, Ssu-Lang Lee, Cheng-Hwai Liou (2009)

RAIRO - Operations Research

This paper studies the machine repair problem consisting of M operating machines with S spare machines, and R servers (repairmen) who leave for a vacation of random length when there are no failed machines queuing up for repair in the repair facility. At the end of the vacation the servers return to the repair facility and operate one of three vacation policies: single vacation, multiple vacation, and hybrid single/multiple vacation. The Markov process and the matrix-geometric approach are used...

Macroscopic non-uniqueness and transversal fluctuation in optimal random sequence alignment

Saba Amsalu, Heinrich Matzinger, Serguei Popov (2007)

ESAIM: Probability and Statistics

We investigate the optimal alignment of two independent random sequences of length n. We provide a polynomial lower bound for the probability of the optimal alignment to be macroscopically non-unique. We furthermore establish a connection between the transversal fluctuation and macroscopic non-uniqueness.

Maintenance policy under multiple unrevealed failure.

Francisco Germán Badía Blasco, M.ª Dolores Berrade Ursúa, Clemente A. Campos (2002)

Qüestiió

The unrevealed failures of a system are detected only by inspection. In this work, an inspection policy along with a maintenance procedure for multiunit systems with dependent times to failure is presented. The existence of an optimum policy is also discussed.

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